The disclosure relates to refrigerated transport systems such as intermodal containers. More particularly, the disclosure relates to refrigerant safety in such refrigerated transport systems.
An exemplary refrigerated intermodal container (also known as a shipping container or intermodal shipping container) has an equipment module at one end of the container. The equipment module contains a vapor compression system having a compressor, a heat rejection heat exchanger downstream of the compressor along a refrigerant flow path, an expansion device, and a heat absorption heat exchanger. One or more first fans may drive an external air flow across the heat rejection heat exchanger. One or more second fans may drive an internal air flow across the heat absorption heat exchanger. In various implementations, for powering the container, there may be a power cord for connecting to an external power source. For ease of manufacture or service, the equipment module may be pre-formed as a module mateable to a remainder of the container body (e.g., insertable into an open front end of the body). One example of such a container refrigeration system is sold by Carrier Corporation of Farmington, Connecticut under the trademark ThinLINE. An example of such a system is seen in U.S. Patent Application 62/098,144, of Rau, filed Dec. 30, 2014 and entitled “Access Panel”, the disclosure of which is incorporated in its entirety herein as if set forth at length. Additionally, refrigerated truck boxes, refrigerated railcars, and the like may have refrigeration systems with different forms or degrees of modularity.
There has been a general move to seek low global warming potential (GWP) refrigerants to replace conventional refrigerants such as R-134a. A number of proposed and possible future replacement refrigerants having low GWP also may have higher flammability and/or toxicity levels than prior refrigerants. These include various hydrofluorocarbon (HFC) and hydrocarbon (HC) refrigerants. Background flame arrestor technology for use with flammable refrigerants is found International Publication No. WO2015/009721A1, published Jan. 22, 2015, the disclosure of which is incorporated herein in its entirety by reference as if set forth at length.
Separately, series loop refrigeration systems have been proposed. An example of such a system is seen in US Patent Application Publication 2014/0260404 A1, of Verma et al., published Sep. 18, 2014, and entitled “High Efficiency Refrigeration System”, the disclosure of which is incorporated in its entirety herein as if set forth at length. Further examples are seen in International Publication Number WO 2015/057299 A1, of Feng et al., published Apr. 23, 2015, and entitled “Two-Phase Refrigeration System” and International Publication Number WO 2015/057297 A1, of Feng et al., published Apr. 23, 2015, and entitled “Operation of a Cascade Air Conditioning System with Two-Phase Loop”, the disclosures of which are incorporated in their entireties herein as if set forth at length.